A light-emitting diode (LED) uses the phenomenon of electroluminescence to convert electricity into light. The core structural element of an LED is the p-n junction. A p-n junction is an interface defined between two types of semiconductor materials (e.g., a p-type and an n-type) within a crystal of a semiconductor. P-n junctions will only conduct electricity in one direction. Hence, LEDs will only generate light when installed with the correct electrical polarity. When a voltage is applied across the p-n junction in the correct direction (i.e., with the anode coupled to the p-side of the p-n junction and the cathode coupled to the n-side of the p-n junction), current flows through the p-n junction and light is emitted from the LED. If the voltage is applied across the p-n junction in the incorrect direction (e.g., with the anode coupled to the n-side of the p-n junction and the cathode coupled to the p-side of the p-n junction), little to no current flows through the p-n junction and no light is emitted. Additionally, when an LED fails, the p-n junction may form an open circuit through which current cannot pass from either direction.
LED technology has increasingly become integrated into mainstream lighting system design. Thus, LED luminaires are commonly used across a wide range of lighting applications. Example lighting applications include residential lighting, industrial lighting, lighting for exit signs, floodlights, linear lighting, and lighting for hazardous applications such as explosion-proof lighting. Compared to traditional light sources, LED luminaires can deliver longer life, enhanced energy efficiency, greater eco-friendliness, greater resistance to vibration, lower maintenance demands and equal or better quality of light. Another significant advantage provided by LED luminaires is the ability of LED luminaires to operate at relatively low temperatures. Low temperature operation is particularly advantageous for lighting applications in hazardous environments such as environments where explosion-proof lighting is required.